1. Field of the Invention
The present invention relates to monitoring the release of radio nuclides contained in gas streams, and more particularly, refers to a new and improved method of obtaining the activity concentration for specific nuclides in waste gases of nuclear installations, by means of high-resolution gamma spectroscopy.
2. Description of the Prior Art
In the operation of nuclear installations, radioactive gases, particularly rare gases, are released into the open air. These releases must be monitored reliably, so that the permissible upper limit, which is set for safety reasons, is not exceeded. Customarely, this monitoring is accomplished by measurement of the .beta.-activity in the stack exhaust air as the sum of the individual components, i.e., without regard to the activity concentration of individual nuclides in the gas mixture.
Since, however, the individual nuclides differ greatly from each other as to their radio toxicity, the maximally permissible emission rates could be utilized optimally if the shares of the individual nuclides in the gas mixture were known. The permissible emission rates are composed of emitted curie/unit of time or Ci/t multiplied by a loading factor specific for each nuclide as illustrated in table I. The actual impact on the environment can therefore be determined only if the emission shares of individual nuclides are known.